Bug in Program?

[GaryFigno]

Hello YuePanEdward. Thank you for sharing your program.

Now i am trying to run your program in my pc, ubuntu 18.04.

I run as your tutorial. However, when the program run into "dataio.batch_read_filenames_in_folder(pc_folder, "_filelist.txt", pc_format, filenames, FLAGS_frame_num_begin, FLAGS_frame_num_end, FLAGS_frame_step);".

There will be an error as follows:

terminate called after throwing an instance of 'std::out_of_range'
what(): basic_string::substr: __pos (which is 18446744073709551615) > this->size() (which is 6)
Aborted (core dumped)

The function call is in line 299 in mulls_slam.cpp

Thank you for sharing the great program.

[GaryFigno]

Sorry for the taking your time.
I solve the problem by rewriting a function to read file.
However, i also meet the problem, "Too few neccessary correspondences".
The sensor i am using is "Hokuyo YVT35x", which can take 1000~2000 point for per scan in 50ms.
I guess the number of points is too few for your algorithm?

Thank you for sharing the great program.

[YuePanEdward]

Thanks for your feedback.

1. The data loader error may be due to the structure of the data folder. The folder for storing the point cloud should only contain the point cloud files (in the format you specified in the run_mulls_slam.sh script). If there's something else in the folder, the mentioned error would occur.
2. I haven't tried the Hokuyo Lidar before. In my opinion, It's a kind of vibrating single-beam LiDAR, similar to the one used in LOAM's original paper. I don't think MULLS can handle such kind of sparse data well. One possible solution is to combine multi-frame data if the frame-wise timestamp is known. I've done it before when testing MULLS with Livox LiDAR.